The number of carcinoma patient has been increasing these days. For example, endometrial endometrioid adenocarcinoma, including endometrial carcinoma and endometrioid adenocarcinoma, is a common gynecological malignancy in the United States. Recently, the incidence of this disease is increasing in Japan. Also, it is known that a significant number of patients with early-stage endometrial endometrioid adenocarcinoma develop both localized recurrence and distant metastasis (Non-patent literature 1).
Meanwhile, for carcinoma patients who have undergone surgical operation, accurate prognostic evaluation in early stage is extremely important for proper post-operative treatment. For example, a chemotherapy having a risk of side effect should be avoided for patients with good prognosis who do not need chemotherapy. On the other hand, appropriate treatment including chemotherapy should be provided to patients who are at high risk of recurrence of carcinoma or reoperation in order to prevent recurrence of carcinoma or to avoid reoperation. Hence, various researches have been conducted to find prognostic factors, however, a credible prognostic factor has not yet being discovered.
With regard to endometrial adenocarcinoma, for example, several clinicopathological indicators are currently used for prognosis, such as the surgical stage of disease, lymph node involvement, myometrial infiltration, histological cell types, differentiation grade of carcinoma, intraperitoneal spread, cervical extension, vascular invasion and the like (non-patent literature 2). However, it cannot be said that the clinicopathological indicators described in the literature are completely reliable indicators for prognosis of endometrial endometrioid adenocarcinoma.
On the other hand, P-LAP is a cell surface aminopeptidase, and is a synonym for oxytocinase (non-patent literature 3). P-LAP is also referred to as insulin-regulated membrane aminopeptidase associated with the glucose transporter 4 (GLUT4) containing vesicles (non-patent literature 4). Recently, it was shown that P-LAP is present in both human endometrial endometrioid adenocarcinoma tissues and cells, and that it works as a regulator of carcinoma cell growth (non-patent literature 5). Also, there has been reported the intriguing changes of P-LAP in normal endometrium during menstrual cycle (non-patent literature 6). However, it has not been known that P-LAP can be a prognostic factor in carcinoma.
(Non-patent literature 1) Am. J. Obstet. Gynecol., 1983; 146: 141-144
(Non-patent literature 2) Gynecol. Oncol., 1991; 40: 55-65
(Non-patent literature 3) Arch. Biochem. Biophys., 1992; 292: 388-392
(Non-patent literature 4) J. Biol. Chem., 1995; 270: 23612-23618
(Non-patent literature 5) Clin. Cancer Res., 2003; 9(4): 1528-1534
(Non-patent literature 6) J. Clin. Endocrinol. Metab., 2002; 87: 1384-1389